drm/gpuvm: rename struct drm_gpuva_manager to struct drm_gpuvm

Rename struct drm_gpuva_manager to struct drm_gpuvm including
corresponding functions. This way the GPUVA manager's structures align
very well with the documentation of VM_BIND [1] and VM_BIND locking [2].

It also provides a better foundation for the naming of data structures
and functions introduced for implementing a common dma-resv per GPU-VM
including tracking of external and evicted objects in subsequent
patches.

[1] Documentation/gpu/drm-vm-bind-async.rst
[2] Documentation/gpu/drm-vm-bind-locking.rst

Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920144343.64830-2-dakr@redhat.com

1 files changed, 705 insertions, 0 deletions

diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h
new file mode 100644
index 000000000000..c7ed6bf441d4
--- /dev/null
+++ b/include/drm/drm_gpuvm.h
@@ -0,0 +1,705 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __DRM_GPUVM_H__
+#define __DRM_GPUVM_H__
+
+/*
+ * Copyright (c) 2022 Red Hat.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/types.h>
+
+#include <drm/drm_gem.h>
+
+struct drm_gpuvm;
+struct drm_gpuvm_ops;
+
+/**
+ * enum drm_gpuva_flags - flags for struct drm_gpuva
+ */
+enum drm_gpuva_flags {
+	/**
+	 * @DRM_GPUVA_INVALIDATED:
+	 *
+	 * Flag indicating that the &drm_gpuva's backing GEM is invalidated.
+	 */
+	DRM_GPUVA_INVALIDATED = (1 << 0),
+
+	/**
+	 * @DRM_GPUVA_SPARSE:
+	 *
+	 * Flag indicating that the &drm_gpuva is a sparse mapping.
+	 */
+	DRM_GPUVA_SPARSE = (1 << 1),
+
+	/**
+	 * @DRM_GPUVA_USERBITS: user defined bits
+	 */
+	DRM_GPUVA_USERBITS = (1 << 2),
+};
+
+/**
+ * struct drm_gpuva - structure to track a GPU VA mapping
+ *
+ * This structure represents a GPU VA mapping and is associated with a
+ * &drm_gpuvm.
+ *
+ * Typically, this structure is embedded in bigger driver structures.
+ */
+struct drm_gpuva {
+	/**
+	 * @vm: the &drm_gpuvm this object is associated with
+	 */
+	struct drm_gpuvm *vm;
+
+	/**
+	 * @flags: the &drm_gpuva_flags for this mapping
+	 */
+	enum drm_gpuva_flags flags;
+
+	/**
+	 * @va: structure containing the address and range of the &drm_gpuva
+	 */
+	struct {
+		/**
+		 * @addr: the start address
+		 */
+		u64 addr;
+
+		/*
+		 * @range: the range
+		 */
+		u64 range;
+	} va;
+
+	/**
+	 * @gem: structure containing the &drm_gem_object and it's offset
+	 */
+	struct {
+		/**
+		 * @offset: the offset within the &drm_gem_object
+		 */
+		u64 offset;
+
+		/**
+		 * @obj: the mapped &drm_gem_object
+		 */
+		struct drm_gem_object *obj;
+
+		/**
+		 * @entry: the &list_head to attach this object to a &drm_gem_object
+		 */
+		struct list_head entry;
+	} gem;
+
+	/**
+	 * @rb: structure containing data to store &drm_gpuvas in a rb-tree
+	 */
+	struct {
+		/**
+		 * @rb: the rb-tree node
+		 */
+		struct rb_node node;
+
+		/**
+		 * @entry: The &list_head to additionally connect &drm_gpuvas
+		 * in the same order they appear in the interval tree. This is
+		 * useful to keep iterating &drm_gpuvas from a start node found
+		 * through the rb-tree while doing modifications on the rb-tree
+		 * itself.
+		 */
+		struct list_head entry;
+
+		/**
+		 * @__subtree_last: needed by the interval tree, holding last-in-subtree
+		 */
+		u64 __subtree_last;
+	} rb;
+};
+
+int drm_gpuva_insert(struct drm_gpuvm *gpuvm, struct drm_gpuva *va);
+void drm_gpuva_remove(struct drm_gpuva *va);
+
+void drm_gpuva_link(struct drm_gpuva *va);
+void drm_gpuva_unlink(struct drm_gpuva *va);
+
+struct drm_gpuva *drm_gpuva_find(struct drm_gpuvm *gpuvm,
+				 u64 addr, u64 range);
+struct drm_gpuva *drm_gpuva_find_first(struct drm_gpuvm *gpuvm,
+				       u64 addr, u64 range);
+struct drm_gpuva *drm_gpuva_find_prev(struct drm_gpuvm *gpuvm, u64 start);
+struct drm_gpuva *drm_gpuva_find_next(struct drm_gpuvm *gpuvm, u64 end);
+
+static inline void drm_gpuva_init(struct drm_gpuva *va, u64 addr, u64 range,
+				  struct drm_gem_object *obj, u64 offset)
+{
+	va->va.addr = addr;
+	va->va.range = range;
+	va->gem.obj = obj;
+	va->gem.offset = offset;
+}
+
+/**
+ * drm_gpuva_invalidate() - sets whether the backing GEM of this &drm_gpuva is
+ * invalidated
+ * @va: the &drm_gpuva to set the invalidate flag for
+ * @invalidate: indicates whether the &drm_gpuva is invalidated
+ */
+static inline void drm_gpuva_invalidate(struct drm_gpuva *va, bool invalidate)
+{
+	if (invalidate)
+		va->flags |= DRM_GPUVA_INVALIDATED;
+	else
+		va->flags &= ~DRM_GPUVA_INVALIDATED;
+}
+
+/**
+ * drm_gpuva_invalidated() - indicates whether the backing BO of this &drm_gpuva
+ * is invalidated
+ * @va: the &drm_gpuva to check
+ */
+static inline bool drm_gpuva_invalidated(struct drm_gpuva *va)
+{
+	return va->flags & DRM_GPUVA_INVALIDATED;
+}
+
+/**
+ * struct drm_gpuvm - DRM GPU VA Manager
+ *
+ * The DRM GPU VA Manager keeps track of a GPU's virtual address space by using
+ * &maple_tree structures. Typically, this structure is embedded in bigger
+ * driver structures.
+ *
+ * Drivers can pass addresses and ranges in an arbitrary unit, e.g. bytes or
+ * pages.
+ *
+ * There should be one manager instance per GPU virtual address space.
+ */
+struct drm_gpuvm {
+	/**
+	 * @name: the name of the DRM GPU VA space
+	 */
+	const char *name;
+
+	/**
+	 * @mm_start: start of the VA space
+	 */
+	u64 mm_start;
+
+	/**
+	 * @mm_range: length of the VA space
+	 */
+	u64 mm_range;
+
+	/**
+	 * @rb: structures to track &drm_gpuva entries
+	 */
+	struct {
+		/**
+		 * @tree: the rb-tree to track GPU VA mappings
+		 */
+		struct rb_root_cached tree;
+
+		/**
+		 * @list: the &list_head to track GPU VA mappings
+		 */
+		struct list_head list;
+	} rb;
+
+	/**
+	 * @kernel_alloc_node:
+	 *
+	 * &drm_gpuva representing the address space cutout reserved for
+	 * the kernel
+	 */
+	struct drm_gpuva kernel_alloc_node;
+
+	/**
+	 * @ops: &drm_gpuvm_ops providing the split/merge steps to drivers
+	 */
+	const struct drm_gpuvm_ops *ops;
+};
+
+void drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name,
+		    u64 start_offset, u64 range,
+		    u64 reserve_offset, u64 reserve_range,
+		    const struct drm_gpuvm_ops *ops);
+void drm_gpuvm_destroy(struct drm_gpuvm *gpuvm);
+
+bool drm_gpuvm_interval_empty(struct drm_gpuvm *gpuvm, u64 addr, u64 range);
+
+static inline struct drm_gpuva *
+__drm_gpuva_next(struct drm_gpuva *va)
+{
+	if (va && !list_is_last(&va->rb.entry, &va->vm->rb.list))
+		return list_next_entry(va, rb.entry);
+
+	return NULL;
+}
+
+/**
+ * drm_gpuvm_for_each_va_range() - iterate over a range of &drm_gpuvas
+ * @va__: &drm_gpuva structure to assign to in each iteration step
+ * @gpuvm__: &drm_gpuvm to walk over
+ * @start__: starting offset, the first gpuva will overlap this
+ * @end__: ending offset, the last gpuva will start before this (but may
+ * overlap)
+ *
+ * This iterator walks over all &drm_gpuvas in the &drm_gpuvm that lie
+ * between @start__ and @end__. It is implemented similarly to list_for_each(),
+ * but is using the &drm_gpuvm's internal interval tree to accelerate
+ * the search for the starting &drm_gpuva, and hence isn't safe against removal
+ * of elements. It assumes that @end__ is within (or is the upper limit of) the
+ * &drm_gpuvm. This iterator does not skip over the &drm_gpuvm's
+ * @kernel_alloc_node.
+ */
+#define drm_gpuvm_for_each_va_range(va__, gpuvm__, start__, end__) \
+	for (va__ = drm_gpuva_find_first((gpuvm__), (start__), (end__) - (start__)); \
+	     va__ && (va__->va.addr < (end__)); \
+	     va__ = __drm_gpuva_next(va__))
+
+/**
+ * drm_gpuvm_for_each_va_range_safe() - safely iterate over a range of
+ * &drm_gpuvas
+ * @va__: &drm_gpuva to assign to in each iteration step
+ * @next__: another &drm_gpuva to use as temporary storage
+ * @gpuvm__: &drm_gpuvm to walk over
+ * @start__: starting offset, the first gpuva will overlap this
+ * @end__: ending offset, the last gpuva will start before this (but may
+ * overlap)
+ *
+ * This iterator walks over all &drm_gpuvas in the &drm_gpuvm that lie
+ * between @start__ and @end__. It is implemented similarly to
+ * list_for_each_safe(), but is using the &drm_gpuvm's internal interval
+ * tree to accelerate the search for the starting &drm_gpuva, and hence is safe
+ * against removal of elements. It assumes that @end__ is within (or is the
+ * upper limit of) the &drm_gpuvm. This iterator does not skip over the
+ * &drm_gpuvm's @kernel_alloc_node.
+ */
+#define drm_gpuvm_for_each_va_range_safe(va__, next__, gpuvm__, start__, end__) \
+	for (va__ = drm_gpuva_find_first((gpuvm__), (start__), (end__) - (start__)), \
+	     next__ = __drm_gpuva_next(va__); \
+	     va__ && (va__->va.addr < (end__)); \
+	     va__ = next__, next__ = __drm_gpuva_next(va__))
+
+/**
+ * drm_gpuvm_for_each_va() - iterate over all &drm_gpuvas
+ * @va__: &drm_gpuva to assign to in each iteration step
+ * @gpuvm__: &drm_gpuvm to walk over
+ *
+ * This iterator walks over all &drm_gpuva structures associated with the given
+ * &drm_gpuvm.
+ */
+#define drm_gpuvm_for_each_va(va__, gpuvm__) \
+	list_for_each_entry(va__, &(gpuvm__)->rb.list, rb.entry)
+
+/**
+ * drm_gpuvm_for_each_va_safe() - safely iterate over all &drm_gpuvas
+ * @va__: &drm_gpuva to assign to in each iteration step
+ * @next__: another &drm_gpuva to use as temporary storage
+ * @gpuvm__: &drm_gpuvm to walk over
+ *
+ * This iterator walks over all &drm_gpuva structures associated with the given
+ * &drm_gpuvm. It is implemented with list_for_each_entry_safe(), and
+ * hence safe against the removal of elements.
+ */
+#define drm_gpuvm_for_each_va_safe(va__, next__, gpuvm__) \
+	list_for_each_entry_safe(va__, next__, &(gpuvm__)->rb.list, rb.entry)
+
+/**
+ * enum drm_gpuva_op_type - GPU VA operation type
+ *
+ * Operations to alter the GPU VA mappings tracked by the &drm_gpuvm.
+ */
+enum drm_gpuva_op_type {
+	/**
+	 * @DRM_GPUVA_OP_MAP: the map op type
+	 */
+	DRM_GPUVA_OP_MAP,
+
+	/**
+	 * @DRM_GPUVA_OP_REMAP: the remap op type
+	 */
+	DRM_GPUVA_OP_REMAP,
+
+	/**
+	 * @DRM_GPUVA_OP_UNMAP: the unmap op type
+	 */
+	DRM_GPUVA_OP_UNMAP,
+
+	/**
+	 * @DRM_GPUVA_OP_PREFETCH: the prefetch op type
+	 */
+	DRM_GPUVA_OP_PREFETCH,
+};
+
+/**
+ * struct drm_gpuva_op_map - GPU VA map operation
+ *
+ * This structure represents a single map operation generated by the
+ * DRM GPU VA manager.
+ */
+struct drm_gpuva_op_map {
+	/**
+	 * @va: structure containing address and range of a map
+	 * operation
+	 */
+	struct {
+		/**
+		 * @addr: the base address of the new mapping
+		 */
+		u64 addr;
+
+		/**
+		 * @range: the range of the new mapping
+		 */
+		u64 range;
+	} va;
+
+	/**
+	 * @gem: structure containing the &drm_gem_object and it's offset
+	 */
+	struct {
+		/**
+		 * @offset: the offset within the &drm_gem_object
+		 */
+		u64 offset;
+
+		/**
+		 * @obj: the &drm_gem_object to map
+		 */
+		struct drm_gem_object *obj;
+	} gem;
+};
+
+/**
+ * struct drm_gpuva_op_unmap - GPU VA unmap operation
+ *
+ * This structure represents a single unmap operation generated by the
+ * DRM GPU VA manager.
+ */
+struct drm_gpuva_op_unmap {
+	/**
+	 * @va: the &drm_gpuva to unmap
+	 */
+	struct drm_gpuva *va;
+
+	/**
+	 * @keep:
+	 *
+	 * Indicates whether this &drm_gpuva is physically contiguous with the
+	 * original mapping request.
+	 *
+	 * Optionally, if &keep is set, drivers may keep the actual page table
+	 * mappings for this &drm_gpuva, adding the missing page table entries
+	 * only and update the &drm_gpuvm accordingly.
+	 */
+	bool keep;
+};
+
+/**
+ * struct drm_gpuva_op_remap - GPU VA remap operation
+ *
+ * This represents a single remap operation generated by the DRM GPU VA manager.
+ *
+ * A remap operation is generated when an existing GPU VA mmapping is split up
+ * by inserting a new GPU VA mapping or by partially unmapping existent
+ * mapping(s), hence it consists of a maximum of two map and one unmap
+ * operation.
+ *
+ * The @unmap operation takes care of removing the original existing mapping.
+ * @prev is used to remap the preceding part, @next the subsequent part.
+ *
+ * If either a new mapping's start address is aligned with the start address
+ * of the old mapping or the new mapping's end address is aligned with the
+ * end address of the old mapping, either @prev or @next is NULL.
+ *
+ * Note, the reason for a dedicated remap operation, rather than arbitrary
+ * unmap and map operations, is to give drivers the chance of extracting driver
+ * specific data for creating the new mappings from the unmap operations's
+ * &drm_gpuva structure which typically is embedded in larger driver specific
+ * structures.
+ */
+struct drm_gpuva_op_remap {
+	/**
+	 * @prev: the preceding part of a split mapping
+	 */
+	struct drm_gpuva_op_map *prev;
+
+	/**
+	 * @next: the subsequent part of a split mapping
+	 */
+	struct drm_gpuva_op_map *next;
+
+	/**
+	 * @unmap: the unmap operation for the original existing mapping
+	 */
+	struct drm_gpuva_op_unmap *unmap;
+};
+
+/**
+ * struct drm_gpuva_op_prefetch - GPU VA prefetch operation
+ *
+ * This structure represents a single prefetch operation generated by the
+ * DRM GPU VA manager.
+ */
+struct drm_gpuva_op_prefetch {
+	/**
+	 * @va: the &drm_gpuva to prefetch
+	 */
+	struct drm_gpuva *va;
+};
+
+/**
+ * struct drm_gpuva_op - GPU VA operation
+ *
+ * This structure represents a single generic operation.
+ *
+ * The particular type of the operation is defined by @op.
+ */
+struct drm_gpuva_op {
+	/**
+	 * @entry:
+	 *
+	 * The &list_head used to distribute instances of this struct within
+	 * &drm_gpuva_ops.
+	 */
+	struct list_head entry;
+
+	/**
+	 * @op: the type of the operation
+	 */
+	enum drm_gpuva_op_type op;
+
+	union {
+		/**
+		 * @map: the map operation
+		 */
+		struct drm_gpuva_op_map map;
+
+		/**
+		 * @remap: the remap operation
+		 */
+		struct drm_gpuva_op_remap remap;
+
+		/**
+		 * @unmap: the unmap operation
+		 */
+		struct drm_gpuva_op_unmap unmap;
+
+		/**
+		 * @prefetch: the prefetch operation
+		 */
+		struct drm_gpuva_op_prefetch prefetch;
+	};
+};
+
+/**
+ * struct drm_gpuva_ops - wraps a list of &drm_gpuva_op
+ */
+struct drm_gpuva_ops {
+	/**
+	 * @list: the &list_head
+	 */
+	struct list_head list;
+};
+
+/**
+ * drm_gpuva_for_each_op() - iterator to walk over &drm_gpuva_ops
+ * @op: &drm_gpuva_op to assign in each iteration step
+ * @ops: &drm_gpuva_ops to walk
+ *
+ * This iterator walks over all ops within a given list of operations.
+ */
+#define drm_gpuva_for_each_op(op, ops) list_for_each_entry(op, &(ops)->list, entry)
+
+/**
+ * drm_gpuva_for_each_op_safe() - iterator to safely walk over &drm_gpuva_ops
+ * @op: &drm_gpuva_op to assign in each iteration step
+ * @next: &next &drm_gpuva_op to store the next step
+ * @ops: &drm_gpuva_ops to walk
+ *
+ * This iterator walks over all ops within a given list of operations. It is
+ * implemented with list_for_each_safe(), so save against removal of elements.
+ */
+#define drm_gpuva_for_each_op_safe(op, next, ops) \
+	list_for_each_entry_safe(op, next, &(ops)->list, entry)
+
+/**
+ * drm_gpuva_for_each_op_from_reverse() - iterate backwards from the given point
+ * @op: &drm_gpuva_op to assign in each iteration step
+ * @ops: &drm_gpuva_ops to walk
+ *
+ * This iterator walks over all ops within a given list of operations beginning
+ * from the given operation in reverse order.
+ */
+#define drm_gpuva_for_each_op_from_reverse(op, ops) \
+	list_for_each_entry_from_reverse(op, &(ops)->list, entry)
+
+/**
+ * drm_gpuva_first_op() - returns the first &drm_gpuva_op from &drm_gpuva_ops
+ * @ops: the &drm_gpuva_ops to get the fist &drm_gpuva_op from
+ */
+#define drm_gpuva_first_op(ops) \
+	list_first_entry(&(ops)->list, struct drm_gpuva_op, entry)
+
+/**
+ * drm_gpuva_last_op() - returns the last &drm_gpuva_op from &drm_gpuva_ops
+ * @ops: the &drm_gpuva_ops to get the last &drm_gpuva_op from
+ */
+#define drm_gpuva_last_op(ops) \
+	list_last_entry(&(ops)->list, struct drm_gpuva_op, entry)
+
+/**
+ * drm_gpuva_prev_op() - previous &drm_gpuva_op in the list
+ * @op: the current &drm_gpuva_op
+ */
+#define drm_gpuva_prev_op(op) list_prev_entry(op, entry)
+
+/**
+ * drm_gpuva_next_op() - next &drm_gpuva_op in the list
+ * @op: the current &drm_gpuva_op
+ */
+#define drm_gpuva_next_op(op) list_next_entry(op, entry)
+
+struct drm_gpuva_ops *
+drm_gpuvm_sm_map_ops_create(struct drm_gpuvm *gpuvm,
+			    u64 addr, u64 range,
+			    struct drm_gem_object *obj, u64 offset);
+struct drm_gpuva_ops *
+drm_gpuvm_sm_unmap_ops_create(struct drm_gpuvm *gpuvm,
+			      u64 addr, u64 range);
+
+struct drm_gpuva_ops *
+drm_gpuvm_prefetch_ops_create(struct drm_gpuvm *gpuvm,
+				 u64 addr, u64 range);
+
+struct drm_gpuva_ops *
+drm_gpuvm_gem_unmap_ops_create(struct drm_gpuvm *gpuvm,
+			       struct drm_gem_object *obj);
+
+void drm_gpuva_ops_free(struct drm_gpuvm *gpuvm,
+			struct drm_gpuva_ops *ops);
+
+static inline void drm_gpuva_init_from_op(struct drm_gpuva *va,
+					  struct drm_gpuva_op_map *op)
+{
+	drm_gpuva_init(va, op->va.addr, op->va.range,
+		       op->gem.obj, op->gem.offset);
+}
+
+/**
+ * struct drm_gpuvm_ops - callbacks for split/merge steps
+ *
+ * This structure defines the callbacks used by &drm_gpuvm_sm_map and
+ * &drm_gpuvm_sm_unmap to provide the split/merge steps for map and unmap
+ * operations to drivers.
+ */
+struct drm_gpuvm_ops {
+	/**
+	 * @op_alloc: called when the &drm_gpuvm allocates
+	 * a struct drm_gpuva_op
+	 *
+	 * Some drivers may want to embed struct drm_gpuva_op into driver
+	 * specific structures. By implementing this callback drivers can
+	 * allocate memory accordingly.
+	 *
+	 * This callback is optional.
+	 */
+	struct drm_gpuva_op *(*op_alloc)(void);
+
+	/**
+	 * @op_free: called when the &drm_gpuvm frees a
+	 * struct drm_gpuva_op
+	 *
+	 * Some drivers may want to embed struct drm_gpuva_op into driver
+	 * specific structures. By implementing this callback drivers can
+	 * free the previously allocated memory accordingly.
+	 *
+	 * This callback is optional.
+	 */
+	void (*op_free)(struct drm_gpuva_op *op);
+
+	/**
+	 * @sm_step_map: called from &drm_gpuvm_sm_map to finally insert the
+	 * mapping once all previous steps were completed
+	 *
+	 * The &priv pointer matches the one the driver passed to
+	 * &drm_gpuvm_sm_map or &drm_gpuvm_sm_unmap, respectively.
+	 *
+	 * Can be NULL if &drm_gpuvm_sm_map is used.
+	 */
+	int (*sm_step_map)(struct drm_gpuva_op *op, void *priv);
+
+	/**
+	 * @sm_step_remap: called from &drm_gpuvm_sm_map and
+	 * &drm_gpuvm_sm_unmap to split up an existent mapping
+	 *
+	 * This callback is called when existent mapping needs to be split up.
+	 * This is the case when either a newly requested mapping overlaps or
+	 * is enclosed by an existent mapping or a partial unmap of an existent
+	 * mapping is requested.
+	 *
+	 * The &priv pointer matches the one the driver passed to
+	 * &drm_gpuvm_sm_map or &drm_gpuvm_sm_unmap, respectively.
+	 *
+	 * Can be NULL if neither &drm_gpuvm_sm_map nor &drm_gpuvm_sm_unmap is
+	 * used.
+	 */
+	int (*sm_step_remap)(struct drm_gpuva_op *op, void *priv);
+
+	/**
+	 * @sm_step_unmap: called from &drm_gpuvm_sm_map and
+	 * &drm_gpuvm_sm_unmap to unmap an existent mapping
+	 *
+	 * This callback is called when existent mapping needs to be unmapped.
+	 * This is the case when either a newly requested mapping encloses an
+	 * existent mapping or an unmap of an existent mapping is requested.
+	 *
+	 * The &priv pointer matches the one the driver passed to
+	 * &drm_gpuvm_sm_map or &drm_gpuvm_sm_unmap, respectively.
+	 *
+	 * Can be NULL if neither &drm_gpuvm_sm_map nor &drm_gpuvm_sm_unmap is
+	 * used.
+	 */
+	int (*sm_step_unmap)(struct drm_gpuva_op *op, void *priv);
+};
+
+int drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm, void *priv,
+		     u64 addr, u64 range,
+		     struct drm_gem_object *obj, u64 offset);
+
+int drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm, void *priv,
+		       u64 addr, u64 range);
+
+void drm_gpuva_map(struct drm_gpuvm *gpuvm,
+		   struct drm_gpuva *va,
+		   struct drm_gpuva_op_map *op);
+
+void drm_gpuva_remap(struct drm_gpuva *prev,
+		     struct drm_gpuva *next,
+		     struct drm_gpuva_op_remap *op);
+
+void drm_gpuva_unmap(struct drm_gpuva_op_unmap *op);
+
+#endif /* __DRM_GPUVM_H__ */